Surgical coagulation forceps are well known for performing endoscopic surgery, which involves coagulating tissue held between forceps blades. Coagulation forceps are known both of the monopolar type and the bipolar type, which use intermittent high frequency current. Kleppinger bipolar forceps, which are used in conjunction with Richard Wolf electrosurgical units, provide coagulation by the bipolar method during a well-known procedure for simultaneous coagulation of both the fallopian tube and the mesosalpinx. Kleppinger bipolar forceps are designed with flat, duck-billed tips or blades on the ends of a pair of forceps spring members. The spring members are insulated and contained within a tube, which, when moved axially, forces the forceps blades together. The Kleppinger bipolar forceps may either be of the syringe type or the scissors type, which refers to the type of manual manipulating handle used by the surgeon outside the patient's body.
Illustrative of the prior art are U.S. Pat. No. 4,005,714 issued Feb. 1, 1977 to Hiltebrandt showing a scissors-type bipolar coagulation forceps, and U.S. Pat. No. 4,819,633 issued Apr. 11, 1989 to Bauer et al. showing a monopolar coagulation forceps, both patents being assigned to Richard Wolf GmbH, these patents being incorporated herein by reference. A description of the operation and maintenance of Kleppinger bipolar forceps used with Richard Wolf Bipolar Systems for procedures involving coagulation of the fallopian tube is found in "Bipolar Instrument Instructions" no. E12C-01-94 issued by Richard Wolf Medical Instruments Corp., which is also incorporated herein by reference.
A well known problem with coagulation forceps after coagulation has been performed by high frequency current or other heat generated during surgical procedures is that tissue adheres to the forceps blades that are in contact with the tissue. When the blades are opened and a portion of tissue adheres to the forceps blades, withdrawal of the forceps from the coagulated tissue can tear the tissue and cause bleeding. Another problem is that the residue of tissue adhering to the forceps blades in the form of ash increases the electrical resistance to the flow of current, requiring a longer time to coagulate the tissue than would be possible if the blades were clean. While it is possible to remove the forceps from the patient, disassemble the forceps and clean the forceps blades, this increases the time required by the surgical procedure.
The prior art has addressed the problem of tissue removal from electrosurgical instruments in various ways.
U.S. Pat. No. 5,423,814 issued Jun. 13, 1995 to Zhu et al. describes an endoscopic bipolar coagulation device enabling the user to clean the electrodes during the procedure without removal from the body. The forceps blades are opened and closed by manipulating a tube with respect to a pair of split frustoconical members formed adjacent the tips of the blades. A cleaning element is suspended from a cleaning rod extending inside the tube. The cleaning rod is slid to scrape the inside edges of the forceps blades. A variation uses a tilting mechanism with control wires on pulleys to actuate the cleaning rod. This leads to a congested area inside the tube.
Other techniques for tissue removal are shown by the following patents. U.S. Pat. No. 4,492,231 issued Jan. 8, 1985 to Auth seeks to avoid sticking of tissue by controlling the RF signal. U.S. Pat. No. 3,685,518 issued Aug. 22, 1972 to Beuerle et al. seeks to prevent adherence by making the blades of a thermally and electrically highly conductive material. Lastly, U.S. Pat. No. 4,307,720 issued Dec. 29, 1981 to Weber, Jr. and U.S. Pat. No. 5,085,657 issued Feb. 4, 1992 to Ben-Simhon employ electrosurgical blades which retract into cleaning housings, which scrape adhered tissue from the blades.
With any type of cleaning element or tissue removal element which is moveable with respect to the forceps blades, there is always the danger of over-extension of the cleaning element past the forceps blades, which could cause possible injury. Means to limit the excursions of the cleaning element are also very desirable in a tissue removal device for forceps.
Accordingly, one object of the present invention is to provide an improved tissue removal device for surgical coagulation forceps.
Another object of the invention is to provide an improved tissue removal device for a standard Kleppinger bipolar forceps, which does not require any modification of the Kleppinger forceps, or at most, only minor modification.
Still another object of the invention is to provide an improved tissue removal device for a bipolar forceps with a motion restrictor, which limits excursions of the cleaning device with respect to the forceps blades.